Explain the differences between process spread and specification spread. 5 stars for best answer. Thanks. Solution CP vs CPK In any industry, understanding the true potential of a process is vital. This will help set realistic goals and aid in avoiding unnecessary pressure to the bodies involved in the process. The demand must be realistic and it should be certain that it is viable and the process is capable of achieving it. To measure process capability, there is a ratio or index being used and this is called as the process capability index. This measures the ability of a particular process to produce a certain output within the limits specified. Process capability is only significant for the kind of processes that can be controlled statistically. Basically, it indicates how much natural variation a process undergoes in relation to the specification limits. It also allows a better comparison between various processes. The Capability Index By using capability indices, one can compare an in-control process output to specification limits. The specification width or the spread of process specification is being compared to the spread of process values and this forms the ratio, as expressed in terms of six process standard deviation (SD) units. There are two known capability indices ‘“ the Cp and Cpk. Both are used to measure process capabilities as they both compare the process spread to the specification spread. However, one is rather more accurate and gives a more clear-cut picture. The Cp index does not take into consideration the placement of process with respect to the given limits or the specification width. In other words, it may be off-center but with cp, it doesn’t matter at all. With that being said, it is the simplest indicator of a process capability. In essence, Cp measures a process’s potential capability thus it is known as the “process potential index”. Mathematically, it is expressed as follows: Cp = (USL – LSL) / (6 x sigma) ; Where: USL = upper specification limit LSL = lower specification limit The drawbacks of Cp are remedied by Cpk. Both are very similar but the latter considers the centering of a particular process distribution. It can be said that it measures the variations between the target (T) and one specification ‘“ either Cpklo or Cpkhi. Cpk is also called as the “process capability index” or “process performance index”. If taken together with Cp, it will express the potential and centering of the distribution of the process within the specified limits. Summary: 1. Cp is the simplest indicator of a process capability while Cpk gives a better picture. 2. Cp is also known as the “process potential index” while Cpk is known as “process capability index” or “process performance index”. 3. Cp index does not take into consideration the placement of process with respect to the given limits or the specification width while Cpk considers the centering of the process distribution. 4. Cp will give a description of form while Cp.

1. Explain the differences between the product design philosophy behind industrial design and
design for manufacture/assembly. Which one do you think is more important in a customer-
focused product development? What factors may need to be traded off by product development
before introducing a new product?
Solution
Product design is cross-functional, knowledge-intensive work that has become increasingly
important in today's fast-paced,globally competitive environment. It is a key strategic activity in
many firms because new products contribute significantly to sales revenue. When firms are able
to develop distinctive products, they have opportunities to command premium pricing. Product
design is a critical factor in organizational success because it sets the characteristics, features,
and performance of the service or good that consumers demand. The objective of product design
is to create a good or service with excellent functional utility and sales appeal at an acceptable
cost and within a reasonable time. The product should be produced using high-quality, low-cost
materials and methods. It should be produced on equipment that is or will be available when
production begins. The resulting product should be competitive with or better than similar
products on the market in terms of quality, appearance, performance, service life, and price.
THE INCREASING IMPORTANCE
OF PRODUCT DESIGN
Product design is more important than ever because customers are demanding greater product
variety and are switching more quickly to products with state-of-the-art technology. The impacts
of greater product variety and shorter product life cycles have a multiplicative effect on the
number of new products and derivative products that need to be designed. For example, just a
few years ago, a firm may have produced four different products and each product may have had
a product life cycle of ten years. In this case, the firm must design four new products every ten
years. Today, in order to be competitive, this firm may produce eight different products with a
life cycle of only five years; this firm must introduce eight new products in five years. That
represents sixteen new products in ten years or one product every seven and one-half months. In
this fast-paced environment, product design ceases to be an ad hoc, intermittent activity and
becomes a regular and routine action. For an organization, delays, problems, and confusion in
product design shift from being an annoyance to being life threatening.
PRODUCT DESIGN AND SUPPLY
CHAIN MANAGEMENT
Product design can also be an important mechanism for coordinating the activities of key supply

2. chain participants. As organizations outsource the production of sub-assemblies and components,
they also may be asking suppliers to participate in product design. As they outsource design
capabilities it is essential that they manage and coordinate the flow of information among the
supply chain participants. This can be especially important as firms outsource components to two
or more suppliers. Now, there may be important design interfaces among two, three, or more
suppliers. These interfaces must be properly managed to ensure cost effective and timely
designs. Clearly, information and communication technologies become important parts of this
effort.
PRODUCT DESIGN: A KEY
TO ORGANIZATIONAL SUCCESS
Product design is an essential activity for firms competing in a global environment. Product
design drives organizational success because it directly and significantly impacts nearly all of the
critical determinants for success. Customers demand greater product variety and are quick to
shift to new, innovative, full-featured products. In addition, customers make purchase decisions
based on a growing list of factors that are affected by product design. Previously, customers
made purchase decisions based primarily on product price and/or quality. While these factors are
still important, customers are adding other dimensions such as customizability, order-to-delivery
time, product safety, and ease and cost of maintenance. Environmental concerns are expanding to
include impacts during production, during the product's operating life, and at the end of its life
(recycle-ability). In addition, customers demand greater protection from defective products,
which leads to lower product liability losses. Safer and longer lasting products lead to enhanced
warrantee provision, which, in turn, impact customer satisfaction and warrantee repair costs.
Programs and activities are being put in place so organizations can cope with these dimensions.
Organizations are embracing concepts such as mass customization, design for manufacturing and
assembly, product disposal, quality function deployment, and time-based competition.They are
using technology such as rapid prototyping and computer-aided design to examine how products
function, how much they may cost to produce, and how they may impact the environment. Firms
are searching for and implementing new technologies to determine ways to design better
products. They are examining legal and ethical issues in product design as well as the impact of
product design on the environment.
MASS CUSTOMIZATION
Mass customization is the low-cost, high-quality, large volume delivery of individually
customized products. It is the ability to quickly design and produce customized products on a
large scale at a cost comparable to non-customized products. Customization, cost effectiveness is
the ability to produce highly differentiated products without increasing costs, significantly.
Consumers expect to receive customized products at close to mass-production prices.

3. Customization volume effectiveness is the ability to increase product variety without diminishing
production volume. As markets become more and more segmented and aggregate demand
remains constant or increases, firms must continue to design and produce high volumes across
the same fixed asset base. Customization responsiveness is the ability to reduce the time required
to deliver customized products and to reorganize design and production processes quickly in
response to customer requests. It would be counter-productive to pursue mass customization if a
customized product takes too long to produce. Speed in product design and production is an
indispensable criterion for evaluating an organization's mass customization capability.
DESIGN FOR MANUFACTURING
AND ASSEMBLY
Improving manufacturability is an important goal for product design. A systems approach to
product design that was developed by two researchers from England, Geoffrey Boothroyd and
Peter Dewhurst, is called design for manufacturability and assembly (DFMA). It can be a
powerful tool to improve product quality and lower manufacturing cost. The approach focuses on
manufacturing issues during product design. DFMA is implemented through computer software
that identifies designs concepts that would be easy to build by focusing on the economic
implications of design decisions. These decisions are critical even though design is a small part
of the overall cost of a product because design decisions fix 70 to 90 percent of the
manufacturing costs. In application, DFMA has had some startling successes. With the DFMA
software, Texas Instruments reduced assembly time for an infrared sighting mechanism from 129
minutes to 20 minutes. IBM sliced assembly time for its printers from thirty minutes to three
minutes.
Firms are recognizing that the concept behind DFMA can also be extended beyond cost control
to design products that are easy to service and maintain. To do this effectively, service and
maintenance issues should be considered at the earliest stages of the design. Also, firms will be
required to examine disposal during product design as they become liable for recycling the
products they make. It can be easier to recycle products if those factors are part of the product
design paradigm.
DISPOSAL AND PRODUCT DESIGN
Disposal is becoming an increasingly important part of product design. The European Union is
taking the lead by requiring that most of an automobile is recycled by the year 2010. This
requirement has a major impact on product design. The most obvious effect is to change the
notion that a consumer is the final owner for a product. With this approach, the product returns to
the manufacturer to be recycled and the recycling process should begin in product design.
Vehicles should be designed so they can be disassembled and recycled easily. The designers
should avoid exotic materials that are difficulty to recycle. For example, parts that have plastic

4. and metal fused together should not be used in applications where they are difficult to separate.
The designers should determine which parts will be designed to be refurbished and reused, and
which will be designed to be discarded, broken down, and recycled. All this should be done
without adding costs or reducing product quality.
QUALITY AND QUALITY
FUNCTION DEPLOYMENT
Product design shapes the product's quality. It defines the way that good and service functions.
Quality has at least two components. First, the product must be designed to function with a high
probability of success, or reliability; that is, it will perform a specific function without failure
under given conditions. When product reliability increases, the firm can extend the product's
warrantee without increasing customer claims for repairs or returns. Warrantees for complex and
expensive items such as appliances are important selling points for customers. Second, quality
improves when operating or performance characteristics improve even though reliability does
not. The goals of product design should be greater performance, greater reliability, and lower
total production and operating costs. Quality and costs should not be viewed as a trade-off
because improvements in product and process technologies can enhance quality and lower costs.
Quality function deployment is being used by organizations to translate customer wants into
working products. Sometimes referred to as the house of quality, quality function deployment
(QFD) is a set of planning and communication routines that focus and coordinate actions and
skills within an organization. The foundation of the house of quality is the belief that a product
should be designed to reflect customers' desires and tastes. The house of quality is a framework
that provides the means for inter-functional planning and communications. Through this
framework, people facing different problems and responsibilities can discuss various design
priorities.
PROTOTYPING
Engineering and operations combine to develop models of products called prototypes. These
may be working models, models reduced in scale, or mock-ups of the products. Where
traditional prototype development often takes weeks or months, the technology for rapid
prototyping has become available. Some companies are using the same technology that creates
virtual reality to develop three-dimensional prototypes. Other firms employ lasers to make
prototypes by solidifying plastic in only a few minutes; this process can produce prototypes with
complex shapes. Prototyping should increase customer satisfaction and improve design stability,
product effectiveness, and the predictability of final product cost and performance.
COMPUTER-AIDED DESIGN
Currently, business managers and engineers perceive computer-aided design (CAD) as a tool to
assist engineers in designing goods. CAD uses computer technology and a graphic display to

5. represent physical shapes in the same way that engineering drawings have in the past. It is used
in the metalworking industry to display component parts, to illustrate size and shape, to show
possible relationships to other parts, and to indicate component deformation under specified
loads. After the design has been completed, the engineer can examine many different views or
sections of the part and finally send it to a plotter to prepare drawings. This capability greatly
reduces engineering time and avoids routine mistakes made in analysis and drawing. It
significantly increases productivity and reduces design time, which allows faster delivery.
Applications of CAD systems are not limited to producing goods. While it's true that services do
not have physical dimensions, the equipment and facilities used to produce services do. For
example, the service stalls in an automotive center or rooms in an emergency medical center
have physical characteristics that can be represented by the interactive graphics capabilities of a
CAD system.
LEGAL AND ETHICAL ISSUES
IN PRODUCT DESIGN
What is the responsibility of an organization and its managers to see that the goods and services
they produce do not harm consumers? Legally, it is very clear that organizations are responsible
for the design and safe use of their products. Consumers who believe they have been damaged by
a poorly designed good or service have legal recourse under both civil and criminal statutes.
Often, however, only the most serious and obvious offenses are settled in this way. More
difficult ethical issues in product design result when the evidence is not as clear. For example,
what responsibilities does a power tool manufacturer have with respect to product safety? Does a
power saw manufacturer have the responsibility to design its product so that it is difficult for a
child to operate? Suppose a parent is using a power saw and is called away to the telephone for a
few minutes. A ten-year old may wander over, press the trigger and be seriously injured.
Designing the saw so it has a simple and inexpensive lockout switch that would have to be
pressed simultaneously when the trigger is pressed would make it more difficult for the accident
to happen. What is the responsibility of the parent? What is the responsibility of the company?
PRODUCT DESIGN
AND THE ENVIRONMENT
Organizations consider product design a critical activity to the production of environmentally
friendly products. Organizations increasingly recognize that being good corporate citizens
increases sales. Fast-food restaurants have begun recycling programs and redesigned packaging
materials and systems in response to customer concerns. In other cases, being a good corporate
citizen and protecting a company's renewable resources go well together; there are win-win
opportunities where an organization can actually design products and processes that cut costs and
increase profits by recapturing pollutants and reducing solid waste.

6. OVERVIEW OF PRODUCT
DESIGN PROCESS
Product design time can be reduced by using a team approach and the early involvement of key
participants including marketing, research and development, engineering, operations, and
suppliers. Early involvement is an approach to managing people and processes. It involves an
upstream investment in time that facilitates the identification and solution of down-stream
problems that would otherwise increase product design and production costs, decrease quality,
and delay product introduction.
Time-based competitors are discovering that reducing product design time improves the
productivity of product design teams. To reduce time, firms are reorganizing product design
from an "over-the-wall" process to a team-based concurrent process. Over-the-wall means to
proceed sequentially with the limited exchange of information and ideas. When this approach is
used, problems are often discovered late because late-stage participants are excluded from
decisions made early in the process. As a result, poor decisions are often made.
Product design is a labor-intensive process that requires the contribution of highly trained
specialists. By using teams of specialists, communications are enhanced, wait time between
decisions is reduced, and productivity is improved. Participants in this team-based process make
better decisions faster because they are building a shared knowledge base that enhances learning
and eases decision-making. By sharing development activities, design decisions that involve
interdependencies between functional specialists can be made more quickly and more
effectively. This reorganized process creates a timely response to customer needs, a more cost-
effective product design process, and higher-quality products at an affordable price.
There are several reasons why early involvement and concurrent activities bring about these
improvements. First, product design shifts from sequential, with feedback loops that occur
whenever a problem is encountered, to concurrent, where problems are recognized early and
resolved. The ability to overlap activities reduces product design time. Second, when a team of
functional specialists works concurrently on product design, the participants learn from each
other and their knowledge base expands. People are better able to anticipate conflicts and can
more easily arrive at solutions. As a result, the time it takes to complete an activity should
decline. Third, fewer changes later in the process results in faster and less expensive product
design. When problems are discovered late, they take more time and money to solve.
Product design requires the expertise and decision-making skills of all parts of the organization.
Marketing, engineering, operations, finance, accounting, and information systems all have
important roles. Marketing's role is to evaluate consumer needs, determine potential impact of
competitive pressure, and measure the external environment. Engineering's role is to shape the
product through design, determine the process by which the product will be made, and consider

7. the interface between the product and the people. Operations' role is to ensure that the product
can be produced in full-scale production. Finance's role is to develop plans for raising the capital
to support the product in full-scale production and to assist in the evaluation of the product's
profit potential. Accounting and information systems provide access to information for decision
making. Cross-functional teamwork and knowledge sharing are thus keys to success.